US2915473A - Detergent compositions - Google Patents

Description

United States Patent DETERGENT COMPOSITIONS Alexander J. Stirton, Philadelphia, James K. Wei], North Wales, and Elmer W. Maurer, Philadelphia, Pa., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Application April 17, 1956 Serial No. 578,850

4 Claims. (Cl. 252-161) (Granted under Title 35, US. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with power to grant sublicensesfor such purposes, is hereby granted to the Government of the United States of America.

This invention relates to improved detergent compositions comprising synergistic mixtures of salts of longchain alkyl sulfates and IZ-SHIfOHatCd fatty acids.

Detergents based on long-chain alkyl sulfates, such as sodium dodecyl sulfate, are well known but suffer from several serious handicaps. In the first place, they are expensive to manufacture so that when sold alone or as the sole active component of a detergent, a premium price must be received. Also, compounds of this type containing 16 or more carbon atoms in the molecule are only slightly soluble in water, thus detracting from their usefulness.

Likewise, the tit-sulfonated fatty acids have long been recognized to have detergent properties in general, but have not found wide use as detergents because of certain deficiencies, particularly their low detergency and poor solubility.

An object of this invention is to provide improved detergent compositions based on sulfated alcohols and sulfonated fatty acids having 16 to 24 carbon atoms and having high detergency and adequate solubility. A par ticular object is to provide such compositions that can be manufactured from the fatty acids present in lard, tallow, grease and fish oils.

Most of the detergent compositions of commerce are mixtures of one or more active components and a builder. By active component is meant a surfaceactive compound, as distinguished from a builder." By the latter term is meant one or more inorganic salts which are added" to the active component to increase its effectiveness, to render the composition granular, to decrease hygroscopicity, or merely to dilute the active component and cheapen the composition. Builders typically consist of salts such as sodium phosphate, silicate, carbonate, sulfate, polyphosphates, borates and the like, or mixtures of such salts.

According to the invention, compositions that are outstanding detergents, either with or without the addition of builders, are obtained by mixing the alkali metal, ammonium or substituted ammonium salts of sulfated aliphatic alcohols with similar salts of a-sulfonated fatty acids, the chain length of both the alcohol and theacid being 16 to 24 carbon atoms and each being present to the extent of at least 10% of the composition, exclusive of builder. These compounds may be represented, respectively, by the following formulas:

RCH CH OSO M and RCHCOOM' OaM wherein R is a straight-chain hydrocarbon radical having 14 to 22 carbon atoms, M is a member selected from the group consisting of alkali metals, ammonium and substituted ammonium radicals, and M is a member of the group consisting of M and hydrogen. A preferred embodiment is that in which the long-chain alcohol is the mixed alcohol obtainable from tallow or grease, bysodium reduction or hydrogenolysis, or from hydrogenated tallow or grease; and the fatty acid is the mixture of saturated acids obtainable by the saponification of tallow or grease, or the mixture of acids obtainable by the saponification of hydrogenated tallow or grease. These preferred alcohols and acids'consist predominantly of C and C compounds, this chain length being the optimum for our detergents. Detergents made from shorter chain compounds tend to be too soluble, less colloidal in character and inferior as detergents. On the other hand, those made from longer chain compounds tend to be only sparingly soluble in cold water. These deficiencies can be largely overcome, however, by blending suitable mixtures of different chain lengths.

A further preferred embodiment is that in which, in addition to the sulfated alcohol and sulfonated fatty acid, a salt of sulfonated dodecylbenzene, having the formula R SOaM .of the active components of the detergent mixture. While alone such alkylbenzenesulfonate is relatively ineffective as. a detergent, in combination with our sulfated alcoholsulfonated acid mixture it showsunexpected efficiency. The relative effectiveness of various detergent compositions was determined in a series of experiments in which 10 swatches of standard soiled cotton cloth were washed for 20 minutes at C. in 1000 ml. of water containing the various detergents. Different lots of standard soiled cotton were used in, Table I than in Table II. Detergency was expressed as the increase in reflectance, AR, after washing. Results of a typical series of experiments are shown in Tables I and II. For convenience the various detergent components. are abbreviated as follows:

X=sodium salt of sulfated hydrogenated tallow alcohol X =sodium salt of sulfated tallow alcohol Y=disodium salt. of tat-sulfonated hydrogenated tallow acid Z=sodium dodecylbenzenesulfonate B=inorganic builder: phosphates, sulfates and silicates TABLEv I Detergency evaluation [Hard water of ppm. (as 02.6092],

Example Composition and Concentration Detergency 0. of Detergent, Percent AR v3 TABLE II Detergency evaluation [Hard water of 300 ppm. (as CaCO Composition and Concentration Detergeney No. 01 Detergent, Percent A R The examples in Tables I and II and other similar experiments show that sodium alkyl sulfates, such as X, are excellent detergents in both hard and soft water while the salts of both a-sulfonated fatty acids and sulfonated dodecylbenzene are relatively poor in both. In the absence of builder (TableI), a combination of X and Y is an excellent detergent,'better than that to be expected from a combination. of a relatively poor detergent (0.04% Y) and a low concentration of X (0.01% X). In the presence of builder, at'20% total active ingredient content, combinations of X and Y, or X and Y, or X, Y and Z are synergistic and better detergents than built 0.05% X. Table II shows synergistic combinations of X and Y, and of X, Y and Z in very hard water.

Various conventional builders were tested and found to differ only slightly in effectiveness. Likewise, replacement of X with X' or with the sodium salt of other sulfated straight-chain aliphatic alcohols having 16 to 24 carbon atoms had no substantial effect on the detergency of the composition. Similarly other a-sulfonated fatty acids having 16 to 24 carbon atoms could be used instead of the hydrogenated tallow acids used in the preparation of 'Y without greatly affecting the detergency of the XY or the XYZ combinations.

The use of potassium, ammonium, mono-, dior triethanolammonium, or mono-, dior trialylammonium salts instead of the sodium salts of the detergents used in the above examples gave substantially similar results, the principal difference being that they were in general more soluble than were the corresponding sodium salts. The ammonium and substituted ammonium salts are particularly useful in detergentcompositions containing no builders, such as in liquid detergents, shampoos and the like.

While our detergent compositions are useful in the form of liquid, flakes, granules or powders, they are particularly advantageous in the formulation of bars.

The requirements for bar detergents are more stringent than for detergents in other physical form because, in addition tothe requirements of effective detergency, suitable solubility, effectiveness in hard water, etc., a bar detergent composition must have the proper physical consistency, lathering properties, cohesiveness,plasticity, affinity for water and mutual compatibility with other constituents to permit ready formation into bars having proper characteristics. The detergent compositions of this invention, described above, have all these desirable characteristics and the unexpected synergistic detergency of the compositions is retained in the bar form. Formulation of these compositions for use in bars is facilitated by the wide range of physical properties attainable by varying the chain length and proportions of the constituents within the specified limits and by appropriate use of the detergent compounds in the form of the various salts specified as operable.

Among the compositions found particularly suitable for use in detergent bars are the following:

1) 15 to 30% of salts of sulfated hydrogenated tallow alcohols, 15 to 30% of sodium dodecylbenzenesulfonate and 40 to of salts of a-sulfonated hydrogenated tallow acids.

(2) 35 to 45% of salts of sulfated tallow alcohols and 55 to 65% of salts of a-sulfonated saturated tallow acids.

Excellent bars were also made from mixtures containing 20 to 40% of triethanolammonium salt and 60 to of sodium salt of a-sulfonated saturated tallow acid, though there was no synergism in detergency.

All the above bar compositions require the use of a small amount of water, about 8 to 16%, for proper plasticity and cohesion.

We claim:

. 1. A detergent composition comprising at least about 10% each of (1) a compound having the formula RCH CH OSO M and (2) a compound having the formula RCHCOOM' SOISM wherein R is a straight-chain aliphatic hydrocarbon radical having 14 to 22 carbon atoms, M is a member selected from the group consisting of alkali metals, ammonium and substituted ammonium radicals, and M is a member of the group consisting of M and hydrogen.

2. A detergent composition as in claim 1 wherein M and M are sodium.

3. A detergent composition comprising at least about 10% each of (1) a compound having the formula RCH CH 0SO M, 2) a compound having the formula RCHCOOM $03M and (3) a compound having the formula References Cited in the file of this patent UNITED STATES PATENTS 1,909,295

Luther May 16, 1933 2,247,741 Beller July 1, 1941 2,477,383 Lewis July 26, 1949 FOREIGN PATENTS 353,475 Great Britain July 24, 1931 494,113 Great Britain Oct. 20, 1938

Claims (1)

1. A DETERGENT COMPOSITION COMPRISING AT LEAST ABOUT 10% EACH OF (1) A COMPOUND HAVING THE FORMULA